This is a traditional Japanese futon. It can be used as a bottom mattress or as a bedcover. It is placed on the floor over tatami mats and creates a bedroom at night. Then it is folded up and placed in a closet during the day to allow the room to be used for another purpose.
This futon was given to me as a wedding gift 50 years ago and came from Japan. While the filling is most likely cotton or synthetic batting, I believe the cover is silk. Since our wedding, this quilt has traveled with us from Los Angeles to New Orleans to St. Louis to San Francisco and finally to Carmel Valley – and it has never been used!